prevent dragging the lander).
The terrain sensors located on the
bottom of the lander (shown in Fig-
ure 9—there were five terrain sensors
in total, wired in parallel) were cus-
tom constructed of a piano wire fila-
ment positioned in the center of small
springs extending down from the bot-
tom of the lander. When the lander
made contact with the ground, any one
or combination of sensors would crush
and the close the sensor circuit. To pre-
vent premature triggering of the terrain
sensors during flight (due to vibration)
a safety relay was utilized which closed
at 32 feet, after the legs were deployed
and locked.
Since the lander and rover were
relatively small in comparison to
the "rough terrain" of field grass and
ground anomalies, the lander was de-
signed to deploy a "terrain normaliza-
tion" mat. The mat was integrated into
the lander legs and functioned much
24 MAY/JUNE 2017 SPORT ROCKETRY
Figure 7. The Mestler Lander, with legs folded
in flight configuration (the fabric mat is not
yet attached to the legs). The lander is
hanging under the Tender Descender
that releases the parachutes after landing.
(Left) Figure 6. Working diagram
of the Mestler Lander structure,
which made heavy use of
3D printed parts.
(Below) Figure 8. The pyro
block containing the Archetype
Rocketry cable cutter. When
the charge fires, the tether is
cut to release the legs and
expose the landing sensors.
